The Relationships among Corn Yields, Leaf Composition and Fertilizers Applied

Abstract

The purpose of this study was to determine the effect of fertilizer application on corn yields and the composition of certain leaves, and the relationships between leaf composition and yields. Three experiments differing in details were conducted under irrigation with hybrid Iowa 939 corn in central Washington. Leaves were selected at several growth stages, but the second leaf below the ear collected at silking was studied most intensively. Analyses were made for total N, P, Ca, Mg, K, and Mn and for P soluble in 2% acetic acid. Only N increased yields significantly; K and P applications did not. Calcium nitrate was least effective of the five N sources used. Total N content of leaves selected prior to silking gave lower correlations with yield than those selected at silking. Yields were highly positively correlated with both N and total P contents of leaves selected at silking, and total P and N contents of leaves were also highly correlated. Partial regression analysis showed that leaf N was probably the dominant determinant of yield, but that the leaf P content was sometimes important. For the three experiments the regression coefficients of yield on leaf N content were not significantly different, but the intercepts were markedly different. In one experiment, yields declined 15 bushels per acre for each leaf per plant showing N deficiency symptoms at silking. The minimum leaf N percentage associated with no evidence of the characteristic tip firing of N deficiency appears to be far below the reported critical N concentrations for maximum yield. Ammonium sulfate produced the highest leaf P and K contents and the lowest Ca and Mg contents in comparison with Ca(NO3)2 and NH4NO3 as N sources. The sum of the determined cations Ca, Mg and K in leaves selected at silking tends to be a constant at about 100 m.c. per 100 gm. Phosphorus soluble in 2% acetic acid was a linear function of and equal to about two‐thirds of the total P over a wide range of total P in the leaves.

Estimating nitrogen fertiliser requirements in maize grain production

“…Total N in ear leaves at 50% silking There was a tendency for the concentration ofN in ear leaves sampled at silking to increase with increasing yield (yield = 2.34 (% N) + 2.46), but the r2 value (0.42) did not permit yields to be directly predicted from N concentrations with acceptable precision. A similar conclusion was reached by Viets et al (1954), who concluded that the effect of unknown and uncontrolled factors on yields made it impossible to derive a critical nutrient level for N by simply sampling growers' crops for leafN content.…”

“…This is slightly higher than most reported values which range from 2.8 to 3.0% (Tyner 1946;Viets et al 1954;Gallo et al 1968;Melsted et al 1969). Bennett et al (1953), however, found the N concentration at 95% of maximum yield fell between 2.6 and 3.1 % whereas Dumenil (1961) gave a range of 2.70-2.85%.…”

Acumulação diferencial de nutrientes por cinco cultivares de milho (Zea mays L.): III - diagnose foliar

“…Vale salientar, que o cultivar Centralmex, que apresentou os níveis foliares mais baixos de Ν, Ρ e Κ deu a mais alta produção de grãos. Além disso, este cultivar possuía os teores mais elevados de Ca e Mg, e, portanto, as menores relações K/Ca + Mg, o que contraria o exposto por VIETS et al (1954), embora estes autores tenham estabelecido o critério de que maiores relações K/Ca + Mg dão maiores produções, para o mesmo cultivar, e no presente caso trata-se de cultivares distintos. Na coleta feita na fase do aparecimento do estilete-estigma, aproximadamente 65 dias após a germinação, as diferenças entre cultivares que apresentaram significância estatística, ao nível de 5%, foram para o Ρ, K, Cu e Fe.…”

Mineral Nutrition and Quality of Maiz (Zea Mays L.) as Affected by Household Waste Compost, Poultry Manure and Inorganic Fertilizers

“…The uptake of nutrients and their distribution to different parts of the maize plants have been found to vary primarily with the fertility of the native soil, application of chemical fertilizers, the growth stage of the plant and the environmental conditions [35]. Several workers found that fertilization with nitrogen increased the concentration of nitrogen and phosphorus in plant tissue [36] as well as increasing potassium concentration in the plant [37].…”